Backward driving assist apparatus for vehicle and method of controlling same

ABSTRACT

Disclosed are a backward driving assist apparatus for a vehicle and a method of controlling the same. The backward driving assist apparatus may include a first collection unit configured to collect one or more forward image frames photographed by a camera when a vehicle moves forward and a driving route generation unit configured to estimate a moving location of the vehicle by matching a wheel pulse count measured by a vehicle speed sensor, a steering angle measured by a steering angle sensor, and a yaw rate measured by a yaw rate sensor when the vehicle moves forward and to generate a forward driving trajectory when the vehicle moves forward, as a backward driving prediction route, through matching of common feature points present in consecutive forward image frames collected by the first collection unit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. § 119(a) toKorean Patent Application No. 10-2018-0123759 filed on Oct. 17, 2018 inthe Korean Intellectual Property Office, which is incorporated herein byreference in its entirety.

BACKGROUND 1. Technical Field

Embodiments of the present disclosure relate to a backward drivingassist apparatus for a vehicle and a method of controlling the same.

2. Related Art

In general, many drivers may have a difficulty in driving when driving avehicle backward.

The reason for this is that the moving trajectory of the backwarddriving of a vehicle is different from that of the forward driving ofthe vehicle. Furthermore, the reason for this is that a driver mustcontrol steering while directly checking several elements, such as arearview mirror, a side mirror and a rear camera, in order to check abackward route and an obstacle when the driver drives the vehiclebackward.

For example, if a driver has to pass through, while driving a vehiclebackward, a road having a narrow width or a road in which vehicles areparked or stopped on the sides of the road backward, the driver has tocheck the interval between obstacles, such as parked or stoppedvehicles, and to drive a vehicle backward by avoiding the obstacleswhile directly determining whether backward driving is possible.Furthermore, a driver's skill and special attention are necessarybecause the driver has to drive a vehicle without being biased to anyone side of the left and right on a backward route while avoiding anobstacle.

Accordingly, a backward driving assist apparatus is being developed sothat a driver can drive a vehicle backward safely and conveniently. Forexample, apparatuses for assisting the backward driving of a vehicleinclude a parking assist system (PAS), a parking guide system (PGS), anda rear monitor.

The background art of the present disclosure is disclosed in KoreanPatent Application Publication No. 2015-0077823 (Jul. 8, 2015 entitled“Auto Backing Route Control System for Vehicle”).

The conventional auto backing route control system for a vehiclesequentially stores driving trajectory data generated when a vehiclemoves forward at given distance intervals, obtains driving trajectorydata in reverse order, stored when the vehicle moves forward and whenthe vehicle moves backward, and controls a backward route.

However, in view of the construction of the vehicle, the radius ofrotation of forward driving is different from that of backward driving.Accordingly, there is a problem in that an error rate is high if abackward driving route is controlled like a forward driving route usingonly a vehicle speed sensor and a steering angle sensor.

The background art is technical information known by the inventor toderive the present disclosure or obtained in the process of deriving thepresent disclosure, and may not be said to be essentially a knowntechnology disclosed to the public before an application for the presentdisclosure is filed.

SUMMARY

Various embodiments are directed to improving driving route controlprecision of a vehicle by correcting a backward driving route of thevehicle based on a change in the features of a forward driving image andbackward driving image captured by a camera.

In an embodiment, a backward driving assist apparatus for a vehicle mayinclude a first collection unit configured to collect one or moreforward image frames photographed by a camera when a vehicle movesforward; a driving route generation unit configured to estimate a movinglocation of the vehicle by matching a wheel pulse count measured by avehicle speed sensor, a steering angle measured by a steering anglesensor, and a yaw rate measured by a yaw rate sensor when the vehiclemoves forward and to generate a forward driving trajectory when thevehicle moves forward, as a backward driving prediction route, throughmatching of common feature points present in consecutive forward imageframes collected by the first collection unit; a second collection unitconfigured to collect one or more backward image frames photographed bythe camera when the vehicle automatically moves backward along thebackward driving prediction route after the forward driving of thevehicle is completed; a deviation calculation unit configured tocalculate a matching deviation between two feature points throughmatching between a feature point of the forward image frame collected bythe first collection unit and a feature point of the backward imageframe collected by the second collection unit and photographed at thesame location as the forward image frame; and a correction driving routegeneration unit configured to generate a backward driving correctionroute corrected from the backward driving prediction route by thematching deviation between the feature points when the vehicleautomatically moves backward along the backward driving predictionroute.

The first collection unit may connect a location of a feature point,included in any one of two consecutive forward image frames, and alocation of a feature point included in the other of the two forwardimage frames using a virtual straight line and calculate a directionangle of the vehicle as an angle formed by the virtual straight line anda horizontal line of the forward image frame.

The first collection unit may exclude a moving object in a series offorward image frames photographed by the camera, from the feature point.

The second collection unit may collect the backward image framephotographed after a movement to a location corresponding to thedirection angle when the vehicle automatically moves backward along thebackward driving prediction route after the forward driving of thevehicle is completed.

In an embodiment, a backward driving assist method for a vehicle mayinclude: collecting, by a first collection unit, one or more forwardimage frames photographed by a camera when a vehicle moves forward;estimating, by a driving route generation unit, a moving location of thevehicle by matching a wheel pulse count measured by a vehicle speedsensor, a steering angle measured by a steering angle sensor, and a yawrate measured by a yaw rate sensor when the vehicle moves forward, andgenerating a forward driving trajectory when the vehicle moves forward,as a backward driving prediction route, through matching of commonfeature points present in consecutive forward image frames collected bythe first collection unit; collecting, by a second collection unit, oneor more backward image frames photographed by the camera when thevehicle automatically moves backward along the backward drivingprediction route after the forward driving of the vehicle is completed;calculating, by a deviation calculation unit, a matching deviationbetween two feature points through matching between a feature point ofthe forward image frame collected by the first collection unit and afeature point of the backward image frame collected by the secondcollection unit and photographed at the same location the forward imageframe; and generating, by a correction driving route generation unit, abackward driving correction route corrected from the backward drivingprediction route by the matching deviation between the feature pointswhen the vehicle automatically moves backward along the backward drivingprediction route.

The method may further include connecting, by the first collection unit,a location of a feature point, included in any one of two consecutiveforward image frames, and a location of a feature point included in theother of the two forward image frames using a virtual straight line, andcalculating a direction angle of the vehicle as an angle formed by thevirtual straight line and a horizontal line of the forward image frame.

The method may further include excluding, by the first collection unit,a moving object in a series of forward image frames photographed by thecamera, from the feature point.

The method may further include collecting, by the second collectionunit, the backward image frame photographed after a movement to alocation corresponding to the direction angle when the vehicleautomatically moves backward along the backward driving prediction routeafter the forward driving of the vehicle is completed.

Other aspects, characteristics and advantages other than the describedones will become evident from the claims and the detailed description ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram shown to schematically describe a backward drivingassist apparatus for a vehicle according to an embodiment of the presentdisclosure.

FIG. 2 is a diagram shown to schematically describe a detailedconfiguration of a controller in the backward driving assist apparatusfor a vehicle shown in FIG. 1.

FIG. 3 is a diagram shown to schematically describe the generation of abackward driving correction route in the backward driving assistapparatus for a vehicle shown in FIG. 1.

FIG. 4 is a flowchart for illustrating a backward driving assist methodfor a vehicle according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

As is traditional in the corresponding field, some exemplary embodimentsmay be illustrated in the drawings in terms of functional blocks, units,and/or modules. Those of ordinary skill in the art will appreciate thatthese block, units, and/or modules are physically implemented byelectronic (or optical) circuits such as logic circuits, discretecomponents, processors, hard-wired circuits, memory elements, wiringconnections, and the like. When the blocks, units, and/or modules areimplemented by processors or similar hardware, they may be programmedand controlled using software (e.g., code) to perform various functionsdiscussed herein. Alternatively, each block, unit, and/or module may beimplemented by dedicated hardware or as a combination of dedicatedhardware to perform some functions and a processor (e.g., one or moreprogrammed processors and associated circuitry) to perform otherfunctions. Each block, unit, and/or module of some exemplary embodimentsmay be physically separated into two or more interacting and discreteblocks, units, and/or modules without departing from the scope of theinventive concept. Further, blocks, units, and/or module of someexemplary embodiments may be physically combined into more complexblocks, units, and/or modules without departing from the scope of theinventive concept.

The merits and characteristics of the present disclosure and a methodfor achieving the merits and characteristics will become more apparentfrom embodiments described in detail in conjunction with theaccompanying drawings. However, the present disclosure is not limited tothe disclosed embodiments, but may be implemented in various differentways and should be understood to include all changes, equivalents orsubstitutes included in the spirit and technical range of the presentdisclosure. The embodiments are provided to only complete the disclosureof the disclosure and to allow those skilled in the art to fullyunderstand the category of the disclosure. In describing the presentdisclosure, a detailed description of a related known technology will beomitted if it is deemed to make the gist of the present inventionunnecessarily vague.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In describing theembodiments with reference to the accompanying drawings, the same orcorresponding element is assigned the same reference numeral, and aredundant description of the same or corresponding element will beomitted.

FIG. 1 is a diagram shown to schematically describe a backward drivingassist apparatus 100 for a vehicle according to an embodiment of thepresent disclosure. Referring to FIG. 1, the backward driving assistapparatus 100 for a vehicle may include a vehicle speed sensor 110, asteering angle sensor 120, a yaw rate sensor 130, a gearshift detector140, a camera 150, a memory 160, an MDPS controller 170, and acontroller 180.

The vehicle speed sensor 110 may count a wheel pulse of a vehicle wheeland provide the wheel pulse count to the controller 180 so that it cancheck a vehicle speed and a moving distance.

The steering angle sensor 120 may measure a steering angle of thesteering wheel of a vehicle and provide the measured steering angle tothe controller 180.

The yaw rate sensor 130 may measure a yaw rate value of a tilted vehiclewhile the vehicle moves, and may provide the measured yaw rate value tothe controller 180.

The gearshift detector 140 may detect the location of a gearshift andprovide the detected location to the controller 180.

The camera 150 may be turned on to photograph (or generate) a series ofimage frames when a vehicle moves forward and/or when a vehicle movesbackward. The camera 150 may include one or more of rear, front and sidecameras 150 capable of photographing a series of forward image frameswhen the vehicle moves forward and photographing a series of backwardimage frames when the vehicle moves backward.

The camera 150 may photograph the subject for photography within aphotographing area using a complementary metal-oxide semiconductor(CMOS) module or a charge coupled device (CCD) module, for example. Aninput image frame (or moving image) is provided to the CMOS module orthe CCD module through a lens. The CMOS module or the CCD module mayconvert the light signal of the subject for photography passing throughthe lens into an electrical signal (or photographing signal), and mayoutput the electrical signal (or photographing signal).

The camera 150 may further include an image processor (not shown). Theimage processor may perform image signal processing on an image frame inorder to reduce noise and to improve picture quality, such as gammacorrection, color filter array interpolation, a color matrix, colorcorrection, or color enhancement. Furthermore, the image processor mayfunctionally perform color processing, blur processing, edge enhancementprocessing, image interpretation processing, image recognitionprocessing, or image effect processing. The image recognition processingmay include face recognition or scene recognition processing. Forexample, the image recognition processing may include brightness leveladjustment, color correction, contrast adjustment, contour enhancementadjustment, screen split processing, the generation of a character imageand the synthesis processing of an image. The image processor may beprovided in the camera 150, may be provided in the controller 180 or maybe provided as a separate device.

The memory 160 may perform a function for temporarily or permanentlystoring data processed by the controller 180. Furthermore, the memory160 may store an image frame photographed by the camera 150 under thecontrol of the controller 180. Furthermore, the memory 160 may store aforward driving trajectory when a vehicle moves forward, as a backwarddriving prediction route, under the control of the controller 180, andmay store a backward driving correction route corrected from thebackward driving prediction route by a matching deviation betweenfeature points.

The memory 160, that is, storage media, may include magnetic storagemedia or flash storage media, but the scope of the present disclosure isnot limited thereto. The memory 160 may include internal storage mediaand/or external storage media. The memory 160 may include volatilestorage media such as DRAM, SRAM, or SDRAM, non-volatile storage mediasuch as one time programmable ROM (OTPROM), PROM, EPROM, EEPROM, maskROM, flash ROM, NAND flash storage media, or NOR flash storage media,flash drives such as an SSD, a compact flash (CF) card, an SD card, amicro-SD card, a mini-SD card, an Xd card, or a memory stick, or astorage device such as an HDD.

The MDPS controller 170 may drive a driving motor (not shown) at atarget steering angle when a vehicle moves forward, may assist forwarddriving by rotating a steering wheel (not shown), may automaticallydrive the driving motor according to a backward driving prediction routeand/or a backward driving correction route after forward driving iscompleted, and may assist backward driving by rotating the steeringwheel.

The controller 180 may estimate the moving location of a vehicle bymatching a wheel pulse count measured by the vehicle speed sensor 110, asteering angle measured by the steering angle sensor 120, and a yaw ratemeasured by the yaw rate sensor 130 when the vehicle moves forward, andmay generate a forward driving trajectory when a vehicle moves forward,as a backward driving prediction route, using a common feature pointpresent in consecutive forward image frames received from the camera150. Furthermore, the controller 180 may calculate a matching deviationbetween two feature points through matching between the feature point ofa forward image frame and the feature point of a backward image framereceived from the camera 150 and photographed at the same location asthe forward image frame, and may generate a backward driving correctionroute corrected from a backward driving prediction route by the matchingdeviation between the feature points.

FIG. 2 is a diagram shown to schematically describe a detailedconfiguration of the controller in the backward driving assist apparatusfor a vehicle shown in FIG. 1. FIG. 3 is a diagram shown toschematically describe the generation of a backward driving correctionroute in the backward driving assist apparatus for a vehicle shown inFIG. 1. Referring to FIG. 2, the controller 180 may include a firstcollection unit 181, a driving route generation unit 182, a secondcollection unit 183, a deviation calculation unit 184 and a correctiondriving route generation unit 185.

The first collection unit 181 may collect one or more forward imageframes photographed by the camera 150 when a vehicle moves forward. Inthe present embodiment, the first collection unit 181 may connect thelocation of a feature point, included in any one of two consecutiveforward image frames, and the location of a feature point included inthe other of the forward image frames using a virtual straight line, andmay calculate the direction angle of a vehicle as an angle formed by thevirtual straight line and the horizontal line of the forward imageframe. Furthermore, when the direction angle is calculated, the firstcollection unit 181 may exclude a moving object in a series of forwardimage frames photographed by the camera 150, from the feature point.This is for reducing an error occurring due to the matching betweenfeature points when a route is generated by excluding a moving objectfrom a feature point and using a fixed object as a feature point. In thepresent embodiment, the function of the first collection unit 181 forcalculating the direction angle may be included in the driving routegeneration unit 182.

The driving route generation unit 182 may estimate the location of avehicle through dead reckoning by matching a wheel pulse count of thevehicle speed sensor 110, a steering angle of the steering angle sensor120, and a yaw rate value of the yaw rate sensor 130. The driving routegeneration unit 182 may generate a forward driving trajectory when avehicle moves forward, as a backward driving prediction route, based ona location estimation value of a vehicle and the matching of commonfeature points present in consecutive forward image frames which arecollected by the first collection unit 181 and to which a directionangle has been applied.

FIG. 3a illustrates a forward driving trajectory 310 (including C→B→A)generated by the driving route generation unit 182 when a vehicle movesforward. For example, the driving route generation unit 182 may generateany one point of the forward driving trajectory 310 through the matchingof feature points 340 present in common in a first forward image frame320 and a second forward image frame 330 consecutive to the firstforward image frame 320. Through such a method, the driving routegeneration unit 182 may generate a forward driving trajectory when avehicle moves forward through the matching of common feature pointspresent in consecutive forward image frames, and may store the generatedforward driving trajectory in the memory 160. The forward drivingtrajectory may be used as a backward driving route.

After the forward driving of the vehicle is completed, the secondcollection unit 183 may collect one or more backward image framesphotographed by the camera 150 when the vehicle automatically movesbackward along the backward driving prediction route stored in thememory 160.

In this case, right before the automatic backward driving, the secondcollection unit 183 may move the camera 150 or the vehicle at adirection angle previously calculated by the first collection unit 181,and may collect backward image frames photographed by the camera 150while the vehicle automatically moves backward along the backwarddriving prediction route.

The reason for this is that if the photographing directions of a forwardimage frame and a backward image frame at the same location aredifferent, images focused on the subject for photography are differentand thus it is impossible to match the images. That is, in the case of avehicle that simply moves forward and a vehicle that simply movesbackward, images captured by the camera 150 at the same location may bedifferent. Accordingly, when a forward image frame is stored in thememory 160, the location and direction of a feature point may bepreviously determined, and a backward image frame may be photographed byincorporating the location and direction into the backward image framewhen a vehicle moves backward.

The deviation calculation unit 184 may calculate a matching deviationbetween two feature points through matching between the feature point ofa forward image frame collected by the first collection unit 181 and thefeature point of a backward image frame collected by the secondcollection unit 183 and photographed at the same location as the forwardimage frame.

FIG. 3b illustrates a backward driving prediction route 350 (includingA→B→C) when a vehicle automatically moves backward after the forwarddriving of the vehicle is completed. For example, FIG. 3b illustrates afirst backward image frame 370 to which the location and direction angleof the feature point 340 of a forward image frame have been applied anda second backward image frame 380 consecutive to the first backwardimage frame 370.

Referring to FIG. 3c , the deviation calculation unit 184 may determinematching between the feature points 340 by comparing the first backwardimage frame 370 including the feature point 340 with the second forwardimage frame 330 including the feature point 340 stored in the memory160, and may calculate a matching deviation φ (e.g., lateral bias)between the feature points 340. In the present embodiment, only thecontents in which a matching deviation is calculated through acomparison between one backward image frame and one forward image framehave been disclosed, but the present disclosure is not limited thereto.For example, a plurality of matching deviations may be calculatedthrough a comparison between a series of backward image framesphotographed on the backward driving prediction route 350 and a seriesof forward image frames stored in the memory 160.

The correction driving route generation unit 185 may generate a backwarddriving correction route (e.g., 360 of FIG. 3) by correcting a backwarddriving prediction route (e.g., 350 of FIG. 3) by a matching deviation φbetween feature points when a vehicle automatically moves backward alongthe backward driving prediction route 350. In this case, the vehicle maymove backward along the backward driving correction route 360.

As described above, driving route control precision can be improved bycorrecting a disturbance (e.g., slip or lateral error), occurringregardless of a road condition when a vehicle automatically movesbackward, through image frame matching.

FIG. 4 is a flowchart for illustrating a backward driving assist methodfor a vehicle according to an embodiment of the present disclosure. Inthe following description, the description of a portion redundant withthe description of FIGS. 1 to 3 will be omitted.

Referring to FIG. 4, at step S410, the backward driving assist apparatus100 collects one or more forward image frames photographed by the camera150 when a vehicle moves forward. In this case, the backward drivingassist apparatus 100 may calculate a direction angle of the vehiclebased on the location of a feature point included in two consecutiveforward image frames in common, and may exclude a moving object in aseries of forward image frames photographed by the camera 150, from thefeature point when calculating the direction angle.

At step S420, the backward driving assist apparatus 100 generates aforward driving trajectory when the vehicle moves forward, as a backwarddriving prediction route, based on a location estimation value of thevehicle, estimated through dead reckoning by matching a wheel pulsecount of the vehicle speed sensor 110, a steering angle of the steeringangle sensor 120, and a yaw rate value of the yaw rate sensor 130, andmatching of common feature points present in consecutive forward imageframes to which the direction angle has been applied.

At step S430, the backward driving assist apparatus 100 collects one ormore backward image frames photographed by the camera 150 when thevehicle automatically moves backward along the backward drivingprediction route after the forward driving of the vehicle is completed.In this case, right before the automatic backward driving, after movingthe camera 150 or the vehicle at the previously calculated directionangle, the backward driving assist apparatus 100 may collect backwardimage frames photographed by the camera 150 while the vehicleautomatically moves backward along the backward driving predictionroute.

At step S440, the backward driving assist apparatus 100 calculates amatching deviation between two feature points through matching betweenthe feature point of a forward image frame and the feature point of abackward image frame photographed at the same location as the forwardimage frame.

At step S450, the backward driving assist apparatus 100 generates abackward driving correction route by correcting the backward drivingprediction route by the matching deviation between the feature pointswhen the vehicle automatically moves backward along the backward drivingprediction route. The vehicle moves backward along the backward drivingcorrection route 360.

According to embodiments, driving route control precision of a vehiclecan be improved by correcting the backward driving route of the vehiclebased on a change in the features of a forward driving image andbackward driving image captured by the camera.

Effects of the present disclosure are not limited to the above-describedeffect, and other effects not described above may be evidentlyunderstood by those skilled in the art from the following description.

The spirit of the present disclosure should not be limited and definedby the above-described embodiments, and all changes equivalently changedfrom the claims and equivalent ones in addition to the claims may besaid to fall within the category of the spirit of the presentdisclosure.

What is claimed is:
 1. A backward driving assist apparatus for avehicle, comprising: a processor configured to: collect two or moreforward image frames photographed by a camera, in response to thevehicle moving forward; calculate a direction angle of the vehicle as anangle formed by a horizontal line of a first forward image frame, of thetwo or more forward image frames, and a virtual straight line connectinga location of a first feature point, included in any one of twoconsecutive forward image frames, and a location of a second featurepoint included in another of the two consecutive forward image frames;estimate respective moving locations of the vehicle by matching a wheelpulse count measured by a vehicle speed sensor, a steering anglemeasured by a steering angle sensor, and a yaw rate measured by a yawrate sensor when the vehicle moves forward; and generate a forwarddriving trajectory when the vehicle moves forward, as a backward drivingprediction route, based on matching of common feature points present inconsecutive forward image frames and the respective moving locations,wherein, for the collection of the two or more forward image frames, theprocessor is further configured to exclude a moving object in a seriesof forward image frames photographed by the camera, from feature pointsused for the calculation of the direction angle.
 2. The backward drivingassist apparatus of claim 1, wherein the processor is further configuredto: collect one or more backward image frames photographed by the camerawhen the vehicle automatically moves backward along the backward drivingprediction route after the forward driving of the vehicle is completed;calculate a matching deviation between two feature points by performinga matching between a feature point of a forward image frame, of the twoor more forward image frames, and a feature point of a backward imageframe, of the one or more backward image frames, photographed at a samelocation as the forward image frame; and generate a backward drivingcorrection route corrected from the backward driving prediction route bythe matching deviation, in response to the vehicle automatically movingbackward along the backward driving prediction route.
 3. The backwarddriving assist apparatus of claim 2, wherein, for the collection of theone or more backward image frames, the processor is further configuredto collect the backward image frame photographed after a movement to alocation corresponding to the direction angle when the vehicleautomatically moves backward along the backward driving prediction routeafter the forward driving of the vehicle is completed.
 4. A backwarddriving assist method for a vehicle, the method comprising: collecting,by a processor, two or more forward image frames photographed by acamera, in response to the vehicle moving forward; calculating adirection angle of the vehicle as an angle formed by a horizontal lineof a first forward image frame, of the two or more forward image frames,and a virtual straight line connected to a location of a first featurepoint, included in any one of two consecutive forward image frames, anda location of a second feature point included in another of the twoconsecutive forward image frames; estimating, by the processor,respective moving locations of the vehicle by matching a wheel pulsecount measured by a vehicle speed sensor, a steering angle measured by asteering angle sensor, and a yaw rate measured by a yaw rate sensor whenthe vehicle moves forward; and generating a forward driving trajectorywhen the vehicle moves forward, as a backward driving prediction route,based on matching of common feature points present in consecutiveforward image frames and the respective moving locations, wherein thecollecting of the two or more forward image frames comprises excluding,by the processor, a moving object in a series of forward image framesphotographed by the camera, from feature points used for the calculationof the direction angle.
 5. The backward driving assist method of claim4, further comprising: collecting, by the processor, one or morebackward image frames photographed by the camera when the vehicleautomatically moves backward along the backward driving prediction routeafter the forward driving of the vehicle is completed; calculating, bythe processor, a matching deviation between two feature points byperforming a matching between a feature point of a forward image frame,of the two or more forward image frames, and a feature point of abackward image frame, of the one or more backward image frames,photographed at a same location as the forward image frame; andgenerating, by the processor, a backward driving correction routecorrected from the backward driving prediction route by the matchingdeviation when the vehicle automatically moves backward along thebackward driving prediction route.
 6. The backward driving assist methodof claim 5, wherein the collecting of the one or more backward imageframes comprises collecting, by the processor, the backward image framephotographed after a movement to a location corresponding to thedirection angle when the vehicle automatically moves backward along thebackward driving prediction route after the forward driving of thevehicle is completed.